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Drop Down Box

Single Selection

The DropDownBox UI component is an editor that consists of a text field and drop-down content. In this demo, the content is the TreeView and the DataGrid in the single selection mode.

The following instructions show how to synchronize the DropDownBox with any other embedded DevExtreme UI component:

  1. Specify data sources
    The DropDownBox's and embedded UI component's data sources can be the same or different. If they are different, the UI component's key field should be present in the DropDownBox's data source.

  2. Specify which data field provides the DropDownBox's values and the embedded UI component's keys
    Assign the field's name to the DropDownBox's valueExpr property and to the key property of the embedded UI component's store.

  3. Synchronize the DropDownBox's value and the embedded UI component's selection
    Bind the DropDownBox's value and the UI component's selectedRowKeys/selectedItemKeys property to the same variable.

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<div class="dx-fieldset"> <div class="dx-field"> <div class="dx-field-label">DropDownBox with embedded TreeView</div> <div class="dx-field-value"> <dx-drop-down-box [(value)]="treeBoxValue" valueExpr="ID" displayExpr="name" placeholder="Select a value..." [showClearButton]="true" [dataSource]="treeDataSource" (onValueChanged)="syncTreeViewSelection($event)" > <div *dxTemplate="let data of 'content'"> <dx-tree-view [dataSource]="treeDataSource" dataStructure="plain" keyExpr="ID" parentIdExpr="categoryId" selectionMode="single" displayExpr="name" [selectByClick]="true" (onContentReady)="$event.component.selectItem(treeBoxValue)" (onItemSelectionChanged)="treeView_itemSelectionChanged($event)" > </dx-tree-view> </div> </dx-drop-down-box> </div> </div> <div class="dx-field"> <div class="dx-field-label">DropDownBox with embedded DataGrid</div> <div class="dx-field-value"> <dx-drop-down-box [(value)]="gridBoxValue" valueExpr="ID" [deferRendering]="false" [displayExpr]="gridBox_displayExpr" placeholder="Select a value..." [showClearButton]="true" [dataSource]="gridDataSource" > <div *dxTemplate="let data of 'content'"> <dx-data-grid [dataSource]="gridDataSource" [columns]="['CompanyName', 'City', 'Phone']" [selection]="{ mode: 'single' }" [hoverStateEnabled]="true" [paging]="{ enabled: true, pageSize: 10 }" [filterRow]="{ visible: true }" [scrolling]="{ mode: 'infinite' }" [(selectedRowKeys)]="gridBoxValue" height="100%" > </dx-data-grid> </div> </dx-drop-down-box> </div> </div> </div>
import { NgModule, Component, ViewChild, enableProdMode } from '@angular/core'; import { BrowserModule } from '@angular/platform-browser'; import { platformBrowserDynamic } from '@angular/platform-browser-dynamic'; import { HttpClient, HttpClientModule } from '@angular/common/http'; import { DxDropDownBoxModule, DxTreeViewModule, DxDataGridModule, DxTreeViewComponent } from 'devextreme-angular'; import CustomStore from 'devextreme/data/custom_store'; if(!/localhost/.test(document.location.host)) { enableProdMode(); } @Component({ selector: 'demo-app', templateUrl: 'app/app.component.html', styleUrls: ['app/app.component.css'] }) export class AppComponent { @ViewChild(DxTreeViewComponent, { static: false }) treeView; treeDataSource: any; treeBoxValue: string; gridDataSource: any; gridBoxValue: number[] = [3]; constructor(private httpClient: HttpClient) { this.treeDataSource = this.makeAsyncDataSource(this.httpClient, "treeProducts.json"); this.gridDataSource = this.makeAsyncDataSource(this.httpClient, "customers.json"); this.treeBoxValue = "1_1"; } makeAsyncDataSource(http, jsonFile){ return new CustomStore({ loadMode: "raw", key: "ID", load: function() { return http.get('../../../../data/' + jsonFile) .toPromise(); } }); }; syncTreeViewSelection() { if (!this.treeView) return; if (!this.treeBoxValue) { this.treeView.instance.unselectAll(); } else { this.treeView.instance.selectItem(this.treeBoxValue); } } treeView_itemSelectionChanged(e){ this.treeBoxValue = e.component.getSelectedNodeKeys(); } gridBox_displayExpr(item){ return item && item.CompanyName + " <" + item.Phone + ">"; } } @NgModule({ imports: [ BrowserModule, DxTreeViewModule, DxDropDownBoxModule, HttpClientModule, DxDataGridModule ], declarations: [AppComponent], bootstrap: [AppComponent] }) export class AppModule { } platformBrowserDynamic().bootstrapModule(AppModule);
:host .dx-fieldset { height: 500px; }
// In real applications, you should not transpile code in the browser. You can see how to create your own application with Angular and DevExtreme here: // https://js.devexpress.com/Documentation/Guide/Angular_Components/Getting_Started/Create_a_DevExtreme_Application/ System.config({ transpiler: 'ts', typescriptOptions: { module: "system", emitDecoratorMetadata: true, experimentalDecorators: true }, meta: { 'typescript': { "exports": "ts" }, 'devextreme/localization.js': { "esModule": true } }, paths: { 'npm:': 'https://unpkg.com/' }, map: { 'ts': 'npm:plugin-typescript@8.0.0/lib/plugin.js', 'typescript': 'npm:typescript@3.5.3/lib/typescript.js', '@angular': 'npm:@angular', 'tslib': 'npm:tslib@2.1.0/tslib.js', 'rxjs': 'npm:rxjs@6.4.0', 'rrule': 'npm:rrule@2.6.6/dist/es5/rrule.js', 'luxon': 'npm:luxon@1.25.0/build/global/luxon.min.js', 'es6-object-assign': 'npm:es6-object-assign@1.1.0', 'devextreme': 'npm:devextreme@20.2.5', 'jszip': 'npm:jszip@3.5.0/dist/jszip.min.js', 'devextreme-quill': 'npm:devextreme-quill@0.9.8/dist/dx-quill.min.js', 'devexpress-diagram': 'npm:devexpress-diagram@2.0.11', 'devexpress-gantt': 'npm:devexpress-gantt@2.0.18', 'devextreme-angular': 'npm:devextreme-angular@20.2.5', 'preact': 'npm:preact@10.5.11/dist/preact.js', 'preact/hooks': 'npm:preact@10.5.11/hooks/dist/hooks.js' }, packages: { 'app': { main: './app.component.ts', defaultExtension: 'ts' }, 'devextreme': { defaultExtension: 'js' }, 'devextreme/events/utils': { main: 'index' }, 'devextreme/events': { main: 'index' }, 'es6-object-assign': { main: './index.js', defaultExtension: 'js' } }, packageConfigPaths: [ "npm:@angular/*/package.json", "npm:@angular/common/*/package.json", "npm:rxjs/package.json", "npm:rxjs/operators/package.json", "npm:devextreme-angular/*/package.json", "npm:devextreme-angular/ui/*/package.json", "npm:devextreme-angular/package.json", "npm:devexpress-diagram/package.json", "npm:devexpress-gantt/package.json", ] });
<!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>DevExtreme Demo</title> <meta http-equiv="X-UA-Compatible" content="IE=edge"/> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/> <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0"/> <link rel="stylesheet" type="text/css" href="https://cdn3.devexpress.com/jslib/20.2.5/css/dx.common.css"/> <link rel="stylesheet" type="text/css" href="https://cdn3.devexpress.com/jslib/20.2.5/css/dx.light.css"/> <script src="https://unpkg.com/core-js@2.4.1/client/shim.min.js"></script> <script src="https://unpkg.com/zone.js@0.10.2/dist/zone.js"></script> <script src="https://unpkg.com/reflect-metadata@0.1.3/Reflect.js"></script> <script src="https://unpkg.com/systemjs@0.21.3/dist/system.js"></script> <script src="config.js"></script> <script> System.import('app').catch(console.error.bind(console)); </script> </head> <body class="dx-viewport"> <div class="demo-container"> <demo-app>Loading...</demo-app> </div> </body> </html>